/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package axil.vm.stack;

import axil.api.AxilObject;
import axil.api.extend.Source;

import static axil.framework.Functions.*;


/**
 * A stack frame that contains no arguments. This is used only when calling a
 * no-arg function.
 */
final class SF0 extends StackFrame {
	SF0() {
	}


	SF0(StackFrame parent, Source source) {
		super(parent, source);
	}


	/**
	 * Get the actual number of parameters passed. The value returned is always
	 * greater than or equal to zero. This is used when dealing with an arbitrary
	 * number of arguments to a function.
	 */
	public int size() {
		return 0;
	}


	public AxilObject a()		{
		throw unreachable();
	}
	public AxilObject b()		{
		throw unreachable();
	}
	public AxilObject c()		{
		throw unreachable();
	}
	public void a(AxilObject v)	{
		throw unreachable();
	}
	public void b(AxilObject v)	{
		throw unreachable();
	}
	public void c(AxilObject v)	{
		throw unreachable();
	}


	public void at(int index, AxilObject value)		{
		throw unreachable();
	}
	public AxilObject at(int index)					{
		throw unreachable();
	}


	/**
	 * Get the value with the given unique ID, or return a null if no such
	 * object can be found in this frame. This does NOT look into the parent
	 * frame.
	 */
	protected AxilObject lookup(int id) {
		if (this == StackFrame.root) {
			throw abort("Cannot find value for variable.", nv("id", id));
		}
		return null;
	}
}
